There is an increased demand for mobile communication in recent years. Particularly, in IMT (International Mobile Telecommunication)-2000 which is regarded as the third generation mobile communications system, realizing high speed and wide area has been incomparably proceeded. Accordingly, it is expected in mobile environment to greatly utilize the multimedia communication such as a dynamic image, by making use of features of the IMT-2000
Under these circumstances, a study of a radio network system whose sharing form is rich in flexibility, pliability, and expandability has been advanced. For example, in Mobile Wireless Internet Forum, the technical report “MTR-007 Open RAN Architecture in the third Generation Mobile Systems Release v1.0.0 (12 Jun. 2001)” was defined.
FIG. 11 is a block diagram showing a functional model of the radio network system in the technical report MTR-007 Open RAN Architecture in the third Generation Mobile Systems Release v1.0.0 (12 Jun. 2001).
In FIG. 11, 30 denotes a radio base station, called Node B, of the third generation mobile communication system. 31 denotes a radio layer 1 which performs notification of system information, investigation of a radio environment, coding/decoding of a radio channel, detection of a random access, measurement of an up-outerloop electric power, control of a down-outerloop electric power, and control of an up-innerloop electric power.
32 denotes an RNC (Radio Network Controller) which is divided into a Control/Drift RNC (Radio Network Controller) 33 and a Serving RNC (Radio Network Controller) 34. The Control/Drift RNC (Radio Network Controller) 33 has each function of 35 through 39 shown below. The Serving RNC (Radio Network Controller) 34 has each function of 39 through 41 shown below.
The Control/Drift RNC 33 performs a control for a common channel. The Serving RNC 34 performs a control for an individual channel.
35 denotes a Cell Bearer Gateway which performs multiplex/separation of a common channel, and broadcast/multicast transmission of a radio bearer.
36 denotes a Cell Controller which performs an assignment and a congestion control concerning a radio resource, an assignment of an individual physical radio resource, an assignment of a common logical radio resource, an assignment and a configuration management of a dynamic common physical resource, a control of a system information notification, a cell environment measurement collection, an assignment of a dynamic channel, cell paging, and a control of down-openloop electric power.
37 denotes a Common Radio Resource Management which performs radio network environmental measurement collection and optimization of network load.
38 denotes a Paging/Broadcast which performs a flow control of broadcast/multicast of a radio bearer, a state notification of broadcast/multicast of a radio bearer, an adjustment of calling a mobile terminal in a multi-cell, and an adjustment of calling a mobile terminal.
39 denotes a UE GEO Location which performs information collection and calculation as to a location of a mobile terminal.
40 denotes a User Radio Gateway which performs segmentation, reassembly, distribution confirmation of an individual channel, header compression, multiplex/separation of an individual channel, macro diversity composition/separation, control processing of up-outerloop electric power, measurement of a radio media access, and encryption of a radio channel.
41 denotes a Mobile Control which performs assignment of an individual logical radio resource, configuration management of an individual physical radio resource, control of a radio individual packet flow, adjustment of an assignment control, management of context of a radio resource, tracing, a setup/release of a connection, control of measurement of a mobile terminal, control of an up-outerloop electric power, adjustment of electric power control of down-outerloop, mapping a radio individual packet flow to a radio QoS, mapping a radio bearer to a transport QoS, location management, control of composition/separation of macro diversity, control of radio channel coding, control of media access measurement, control of a TDD timing, measurement and calculation of a radio frame distribution, an individual calling of a mobile terminal, and a handover control.
The functional model of the radio network system shown in FIG. 11 has a feature, in order to obtain flexibility, pliability and expandability, that the transport layer is completely separated from the radio network layer, and the radio network layer is divided into a Signaling Plane including each function of 36 through 39 and 41 and a Bearer Plane including each function of 35 and 40.
In the above-mentioned conventional system, the radio network layer is divided into the Signaling Plane and the Bearer Plane to define the functional block, in order to have flexibility, pliability and expandability. However, there is a problem that it has not been clarified how to proceed the load sharing when a radio network layer is realized by a plurality of apparatuses including the same functional block.
Thus, it is an object of the preferred embodiments of the present invention of the radio network system and the radio communications control method to proceed the load sharing among a plurality of apparatuses in the case of realizing one functional block by a plurality of apparatuses including the same functional block.
Moreover, it is another object of the preferred embodiments of the present invention of the radio network system and the radio communications control method to efficiently perform the load sharing of a plurality of Radio Bearer Servers which realize the function of the Bearer Plane (user plane).